“This study builds on studies in which we demonstrated that motor neurons can be generated from mouse embryonic stem cells,” says Dr. Rafuse, “It’s very exciting that these neurons can be used for transplantation to prevent degeneration of muscle.”

Dalhousie Medical School researchers have discovered that embryonic stem cells may play a critical role in helping people with nerve damage and motor neuron diseases, such as amyotrophic lateral sclerosis (ALS), regain muscular strength.

Motor neurons reside in the spinal cord and control limb movements by enabling muscles to contract. Diseases like ALS cause them to degenerate, resulting in muscle weakness, atrophy, and eventual paralysis.

“This study builds on a series of studies in which we demonstrated that motor neurons can be generated from mouse embryonic stem cells,” says Dr. Victor Rafuse, associate professor of anatomy and neurobiology. “It’s very exciting that these neurons can be used for transplantation to prevent degeneration of muscle.”

The research team used embryonic stem cells from mice to grow motor neurons in the laboratory. They then transplanted the neurons into mouse nerves that were separated from the spinal cord. After separation, it would be expected that the nerves and muscles they control die. However, the Dalhousie group was the first in the world to find that the muscles not only were preserved by the transplantation, but they could produce about half their normal force to contract.

“This opens the door for a variety of different treatments,” says Dr. Rob Brownstone, professor of surgery and anatomy and neurobiology. “We’ve learned that muscles are preserved by stem cells; now we’re studying how this method can be applied to humans so that we can better treat people with nerve injuries and paralysis. Additionally, we’re looking at combining stem cell treatment with electrically-stimulated implants, which could stimulate nerves to produce movement.”